2 * devfreq_cooling: Thermal cooling device implementation for devices using
5 * Copyright (C) 2014-2015 ARM Limited
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
11 * This program is distributed "as is" WITHOUT ANY WARRANTY of any
12 * kind, whether express or implied; without even the implied warranty
13 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
17 * - If OPPs are added or removed after devfreq cooling has
18 * registered, the devfreq cooling won't react to it.
21 #include <linux/devfreq.h>
22 #include <linux/devfreq_cooling.h>
23 #include <linux/export.h>
24 #include <linux/idr.h>
25 #include <linux/slab.h>
26 #include <linux/pm_opp.h>
27 #include <linux/thermal.h>
29 #include <trace/events/thermal.h>
31 static DEFINE_IDA(devfreq_ida
);
34 * struct devfreq_cooling_device - Devfreq cooling device
35 * @id: unique integer value corresponding to each
36 * devfreq_cooling_device registered.
37 * @cdev: Pointer to associated thermal cooling device.
38 * @devfreq: Pointer to associated devfreq device.
39 * @cooling_state: Current cooling state.
40 * @power_table: Pointer to table with maximum power draw for each
41 * cooling state. State is the index into the table, and
43 * @freq_table: Pointer to a table with the frequencies sorted in descending
44 * order. You can index the table by cooling device state
45 * @freq_table_size: Size of the @freq_table and @power_table
46 * @power_ops: Pointer to devfreq_cooling_power, used to generate the
49 struct devfreq_cooling_device
{
51 struct thermal_cooling_device
*cdev
;
52 struct devfreq
*devfreq
;
53 unsigned long cooling_state
;
56 size_t freq_table_size
;
57 struct devfreq_cooling_power
*power_ops
;
61 * partition_enable_opps() - disable all opps above a given state
62 * @dfc: Pointer to devfreq we are operating on
63 * @cdev_state: cooling device state we're setting
65 * Go through the OPPs of the device, enabling all OPPs until
66 * @cdev_state and disabling those frequencies above it.
68 static int partition_enable_opps(struct devfreq_cooling_device
*dfc
,
69 unsigned long cdev_state
)
72 struct device
*dev
= dfc
->devfreq
->dev
.parent
;
74 for (i
= 0; i
< dfc
->freq_table_size
; i
++) {
75 struct dev_pm_opp
*opp
;
77 unsigned int freq
= dfc
->freq_table
[i
];
78 bool want_enable
= i
>= cdev_state
? true : false;
80 opp
= dev_pm_opp_find_freq_exact(dev
, freq
, !want_enable
);
82 if (PTR_ERR(opp
) == -ERANGE
)
90 ret
= dev_pm_opp_enable(dev
, freq
);
92 ret
= dev_pm_opp_disable(dev
, freq
);
101 static int devfreq_cooling_get_max_state(struct thermal_cooling_device
*cdev
,
102 unsigned long *state
)
104 struct devfreq_cooling_device
*dfc
= cdev
->devdata
;
106 *state
= dfc
->freq_table_size
- 1;
111 static int devfreq_cooling_get_cur_state(struct thermal_cooling_device
*cdev
,
112 unsigned long *state
)
114 struct devfreq_cooling_device
*dfc
= cdev
->devdata
;
116 *state
= dfc
->cooling_state
;
121 static int devfreq_cooling_set_cur_state(struct thermal_cooling_device
*cdev
,
124 struct devfreq_cooling_device
*dfc
= cdev
->devdata
;
125 struct devfreq
*df
= dfc
->devfreq
;
126 struct device
*dev
= df
->dev
.parent
;
129 if (state
== dfc
->cooling_state
)
132 dev_dbg(dev
, "Setting cooling state %lu\n", state
);
134 if (state
>= dfc
->freq_table_size
)
137 ret
= partition_enable_opps(dfc
, state
);
141 dfc
->cooling_state
= state
;
147 * freq_get_state() - get the cooling state corresponding to a frequency
148 * @dfc: Pointer to devfreq cooling device
149 * @freq: frequency in Hz
151 * Return: the cooling state associated with the @freq, or
152 * THERMAL_CSTATE_INVALID if it wasn't found.
155 freq_get_state(struct devfreq_cooling_device
*dfc
, unsigned long freq
)
159 for (i
= 0; i
< dfc
->freq_table_size
; i
++) {
160 if (dfc
->freq_table
[i
] == freq
)
164 return THERMAL_CSTATE_INVALID
;
168 * get_static_power() - calculate the static power
169 * @dfc: Pointer to devfreq cooling device
170 * @freq: Frequency in Hz
172 * Calculate the static power in milliwatts using the supplied
173 * get_static_power(). The current voltage is calculated using the
174 * OPP library. If no get_static_power() was supplied, assume the
175 * static power is negligible.
178 get_static_power(struct devfreq_cooling_device
*dfc
, unsigned long freq
)
180 struct devfreq
*df
= dfc
->devfreq
;
181 struct device
*dev
= df
->dev
.parent
;
182 unsigned long voltage
;
183 struct dev_pm_opp
*opp
;
185 if (!dfc
->power_ops
->get_static_power
)
188 opp
= dev_pm_opp_find_freq_exact(dev
, freq
, true);
189 if (PTR_ERR(opp
) == -ERANGE
)
190 opp
= dev_pm_opp_find_freq_exact(dev
, freq
, false);
193 dev_err_ratelimited(dev
, "Failed to find OPP for frequency %lu: %ld\n",
198 voltage
= dev_pm_opp_get_voltage(opp
) / 1000; /* mV */
202 dev_err_ratelimited(dev
,
203 "Failed to get voltage for frequency %lu\n",
208 return dfc
->power_ops
->get_static_power(df
, voltage
);
212 * get_dynamic_power - calculate the dynamic power
213 * @dfc: Pointer to devfreq cooling device
214 * @freq: Frequency in Hz
215 * @voltage: Voltage in millivolts
217 * Calculate the dynamic power in milliwatts consumed by the device at
218 * frequency @freq and voltage @voltage. If the get_dynamic_power()
219 * was supplied as part of the devfreq_cooling_power struct, then that
220 * function is used. Otherwise, a simple power model (Pdyn = Coeff *
221 * Voltage^2 * Frequency) is used.
224 get_dynamic_power(struct devfreq_cooling_device
*dfc
, unsigned long freq
,
225 unsigned long voltage
)
229 struct devfreq_cooling_power
*dfc_power
= dfc
->power_ops
;
231 if (dfc_power
->get_dynamic_power
)
232 return dfc_power
->get_dynamic_power(dfc
->devfreq
, freq
,
235 freq_mhz
= freq
/ 1000000;
236 power
= (u64
)dfc_power
->dyn_power_coeff
* freq_mhz
* voltage
* voltage
;
237 do_div(power
, 1000000000);
242 static int devfreq_cooling_get_requested_power(struct thermal_cooling_device
*cdev
,
243 struct thermal_zone_device
*tz
,
246 struct devfreq_cooling_device
*dfc
= cdev
->devdata
;
247 struct devfreq
*df
= dfc
->devfreq
;
248 struct devfreq_dev_status
*status
= &df
->last_status
;
250 unsigned long freq
= status
->current_frequency
;
251 u32 dyn_power
, static_power
;
253 /* Get dynamic power for state */
254 state
= freq_get_state(dfc
, freq
);
255 if (state
== THERMAL_CSTATE_INVALID
)
258 dyn_power
= dfc
->power_table
[state
];
260 /* Scale dynamic power for utilization */
261 dyn_power
= (dyn_power
* status
->busy_time
) / status
->total_time
;
263 /* Get static power */
264 static_power
= get_static_power(dfc
, freq
);
266 trace_thermal_power_devfreq_get_power(cdev
, status
, freq
, dyn_power
,
269 *power
= dyn_power
+ static_power
;
274 static int devfreq_cooling_state2power(struct thermal_cooling_device
*cdev
,
275 struct thermal_zone_device
*tz
,
279 struct devfreq_cooling_device
*dfc
= cdev
->devdata
;
283 if (state
>= dfc
->freq_table_size
)
286 freq
= dfc
->freq_table
[state
];
287 static_power
= get_static_power(dfc
, freq
);
289 *power
= dfc
->power_table
[state
] + static_power
;
293 static int devfreq_cooling_power2state(struct thermal_cooling_device
*cdev
,
294 struct thermal_zone_device
*tz
,
295 u32 power
, unsigned long *state
)
297 struct devfreq_cooling_device
*dfc
= cdev
->devdata
;
298 struct devfreq
*df
= dfc
->devfreq
;
299 struct devfreq_dev_status
*status
= &df
->last_status
;
300 unsigned long freq
= status
->current_frequency
;
301 unsigned long busy_time
;
306 static_power
= get_static_power(dfc
, freq
);
308 dyn_power
= power
- static_power
;
309 dyn_power
= dyn_power
> 0 ? dyn_power
: 0;
311 /* Scale dynamic power for utilization */
312 busy_time
= status
->busy_time
?: 1;
313 dyn_power
= (dyn_power
* status
->total_time
) / busy_time
;
316 * Find the first cooling state that is within the power
317 * budget for dynamic power.
319 for (i
= 0; i
< dfc
->freq_table_size
- 1; i
++)
320 if (dyn_power
>= dfc
->power_table
[i
])
324 trace_thermal_power_devfreq_limit(cdev
, freq
, *state
, power
);
328 static struct thermal_cooling_device_ops devfreq_cooling_ops
= {
329 .get_max_state
= devfreq_cooling_get_max_state
,
330 .get_cur_state
= devfreq_cooling_get_cur_state
,
331 .set_cur_state
= devfreq_cooling_set_cur_state
,
335 * devfreq_cooling_gen_tables() - Generate power and freq tables.
336 * @dfc: Pointer to devfreq cooling device.
338 * Generate power and frequency tables: the power table hold the
339 * device's maximum power usage at each cooling state (OPP). The
340 * static and dynamic power using the appropriate voltage and
341 * frequency for the state, is acquired from the struct
342 * devfreq_cooling_power, and summed to make the maximum power draw.
344 * The frequency table holds the frequencies in descending order.
345 * That way its indexed by cooling device state.
347 * The tables are malloced, and pointers put in dfc. They must be
348 * freed when unregistering the devfreq cooling device.
350 * Return: 0 on success, negative error code on failure.
352 static int devfreq_cooling_gen_tables(struct devfreq_cooling_device
*dfc
)
354 struct devfreq
*df
= dfc
->devfreq
;
355 struct device
*dev
= df
->dev
.parent
;
358 u32
*power_table
= NULL
;
362 num_opps
= dev_pm_opp_get_opp_count(dev
);
364 if (dfc
->power_ops
) {
365 power_table
= kcalloc(num_opps
, sizeof(*power_table
),
371 freq_table
= kcalloc(num_opps
, sizeof(*freq_table
),
375 goto free_power_table
;
378 for (i
= 0, freq
= ULONG_MAX
; i
< num_opps
; i
++, freq
--) {
379 unsigned long power_dyn
, voltage
;
380 struct dev_pm_opp
*opp
;
382 opp
= dev_pm_opp_find_freq_floor(dev
, &freq
);
388 voltage
= dev_pm_opp_get_voltage(opp
) / 1000; /* mV */
391 if (dfc
->power_ops
) {
392 power_dyn
= get_dynamic_power(dfc
, freq
, voltage
);
394 dev_dbg(dev
, "Dynamic power table: %lu MHz @ %lu mV: %lu = %lu mW\n",
395 freq
/ 1000000, voltage
, power_dyn
, power_dyn
);
397 power_table
[i
] = power_dyn
;
400 freq_table
[i
] = freq
;
404 dfc
->power_table
= power_table
;
406 dfc
->freq_table
= freq_table
;
407 dfc
->freq_table_size
= num_opps
;
420 * of_devfreq_cooling_register_power() - Register devfreq cooling device,
421 * with OF and power information.
422 * @np: Pointer to OF device_node.
423 * @df: Pointer to devfreq device.
424 * @dfc_power: Pointer to devfreq_cooling_power.
426 * Register a devfreq cooling device. The available OPPs must be
427 * registered on the device.
429 * If @dfc_power is provided, the cooling device is registered with the
430 * power extensions. For the power extensions to work correctly,
431 * devfreq should use the simple_ondemand governor, other governors
432 * are not currently supported.
434 struct thermal_cooling_device
*
435 of_devfreq_cooling_register_power(struct device_node
*np
, struct devfreq
*df
,
436 struct devfreq_cooling_power
*dfc_power
)
438 struct thermal_cooling_device
*cdev
;
439 struct devfreq_cooling_device
*dfc
;
440 char dev_name
[THERMAL_NAME_LENGTH
];
443 dfc
= kzalloc(sizeof(*dfc
), GFP_KERNEL
);
445 return ERR_PTR(-ENOMEM
);
450 dfc
->power_ops
= dfc_power
;
452 devfreq_cooling_ops
.get_requested_power
=
453 devfreq_cooling_get_requested_power
;
454 devfreq_cooling_ops
.state2power
= devfreq_cooling_state2power
;
455 devfreq_cooling_ops
.power2state
= devfreq_cooling_power2state
;
458 err
= devfreq_cooling_gen_tables(dfc
);
462 err
= ida_simple_get(&devfreq_ida
, 0, 0, GFP_KERNEL
);
467 snprintf(dev_name
, sizeof(dev_name
), "thermal-devfreq-%d", dfc
->id
);
469 cdev
= thermal_of_cooling_device_register(np
, dev_name
, dfc
,
470 &devfreq_cooling_ops
);
473 dev_err(df
->dev
.parent
,
474 "Failed to register devfreq cooling device (%d)\n",
484 ida_simple_remove(&devfreq_ida
, dfc
->id
);
486 kfree(dfc
->power_table
);
487 kfree(dfc
->freq_table
);
493 EXPORT_SYMBOL_GPL(of_devfreq_cooling_register_power
);
496 * of_devfreq_cooling_register() - Register devfreq cooling device,
497 * with OF information.
498 * @np: Pointer to OF device_node.
499 * @df: Pointer to devfreq device.
501 struct thermal_cooling_device
*
502 of_devfreq_cooling_register(struct device_node
*np
, struct devfreq
*df
)
504 return of_devfreq_cooling_register_power(np
, df
, NULL
);
506 EXPORT_SYMBOL_GPL(of_devfreq_cooling_register
);
509 * devfreq_cooling_register() - Register devfreq cooling device.
510 * @df: Pointer to devfreq device.
512 struct thermal_cooling_device
*devfreq_cooling_register(struct devfreq
*df
)
514 return of_devfreq_cooling_register(NULL
, df
);
516 EXPORT_SYMBOL_GPL(devfreq_cooling_register
);
519 * devfreq_cooling_unregister() - Unregister devfreq cooling device.
520 * @dfc: Pointer to devfreq cooling device to unregister.
522 void devfreq_cooling_unregister(struct thermal_cooling_device
*cdev
)
524 struct devfreq_cooling_device
*dfc
;
531 thermal_cooling_device_unregister(dfc
->cdev
);
532 ida_simple_remove(&devfreq_ida
, dfc
->id
);
533 kfree(dfc
->power_table
);
534 kfree(dfc
->freq_table
);
538 EXPORT_SYMBOL_GPL(devfreq_cooling_unregister
);